Uneasiness, extreme fatigue, reduced performance, dejection, insomnia, loss of enjoyment: these are some of the most frequent signs of depression. When left untreated depression plays havoc with its victims: their professional and academic lives suffer, as do their relationships. A young mother may stop taking care of her baby, a child will fail to keep up at school, an adolescent may adopt dangerous behaviour, an elderly man may decide to end his life.

What are the real causes of depression: lack of affection, personal fragility or a series of traumatic events?

Major advances in the science of the brain have enabled the association of neurobiology and psychology to give us a better understanding of depression. Medication and psychotherapy are the two pillars of a treatment that works.

In France, one out of five people suffers from depression, but of these only one out of three receives treatment. Six million people are on antidepressants.

Included here are a series of questions and answers illustrated with numerous examples: Am I suffering from a passing case of the doldrums or from real depression? What is known about the inner workings of depression? How can it be treated? Can it be prevented? How can I help a loved one who is suffering from depression?

It is crucial to detect the first signs of depression and to treat the condition right away. This will shorten victims' suffering, enable them to get on with their lives, and keep them from settling into a situation of chronic depression.

The authors tell us everything we should know about depression today, from the earliest symptoms to its treatment and cure.

Henri Lôo is the head of the Psychiatry Department at Hôpital Sainte Anne, in Paris.

David Gourion, a psychiatrist, is an assistant in Psychiatry at Hôpital Sainte Anne.